People having lung problems often require supplemental oxygen. Conventionally, if these people want mobility while using supplemental oxygen, they must either pull a cart with an attached bottle or carry the bottle in a shoulder sling or a case carried in the hand. In each case, the person loses mobility of either one arm or one hand.
Oxygen containers which may be carried or towed typically contain between 164 and 415 liters (5 and 14 cubic feet) of oxygen. The typical flow rates can be controlled between 0.5 and 6 liters/min. The oxygen can be contained as a gas or liquid.